1. Field of the Invention
The present invention relates to a magnetic refrigerator comprising working substances for the magnetic refrigeration and a magnetic field generating device which can vary the distribution or strength of magnetic fields applied to the working substances, and it relates in particular to a magnetic refrigerator which is suitable for providing highly efficient refrigeration.
2. Description of the Prior Art
A magnetic refrigerator known heretofore is of the reciprocating type, as disclosed in the specification of U.S. Pat. No. 4,332,135. This reciprocating type of refrigerator wherein a working substance is moved into and out of a high magnetic field by a reciprocating motion requires a complicated mechanism for driving the working substance and a large structure for the entire refrigerator. A rotary type of magnetic refrigerator, as disclosed in the specification of U.S. Pat. No. 4,107,935, which rotates the working substance, is known as well, but the refrigerator of this type has an inevitable problem concerning the fluidtightness since a heat-exchanging medium flows through a rotating body, and requires a very complicated construction since means for circulating the fluid, etc., are required.